In astronomy

Astronomy

Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 the mirror support cell - more commonly mirror cell - is the component of a reflecting telescope

Reflecting telescope

A reflecting telescope is an optical telescope which uses a single or combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century as an alternative to the refracting telescope which, at that time, was a design that suffered from...

 which supports the mirror in place to hold optical alignment, allow collimation adjustment, and protect it from falling out. The common usage of the word denotes the cell holding the primary mirror

Primary mirror

A primary mirror is the principal light-gathering surface of a reflecting telescope.-Description:The primary mirror of a reflecting telescope is a spherical or parabolic shaped disks of polished reflective metal , or in later telescopes, glass or other material coated with a reflective layer...

 (M1), however technically it could also be used to denote the support assembly (usually called a spider or strut) for the secondary mirror (M2) or other mirrors.

Basic cells

A basic mirror cell may be built using minimal calculation and simple materials such as wood and outdoor carpet, as in the original Dobsonian telescope

Dobsonian telescope

A Dobsonian telescope is an alt-azimuth mounted newtonian telescope design popularized by the amateur astronomer John Dobson starting in the 1960s. Dobson's telescopes featured a simplified mechanical design that was easy to manufacture from readily available components to create a large, portable,...

s. Only slightly more complex are the wooden, plastic or metal cells which are often glued and which are either not user adjustable or which have only limited adjustment and which are used in lower end commercial scopes and smaller amateur-built scopes.

Cells for more sophisticated "small" telescopes

Telescope makers seeking to build larger "small" telescopes with thinner mirrors find simple designs inadequate so they must resort to more complex design methods which include possible use of multiaxis adjustment potential and floating whiffletree cell design, often optimimized using computer aided design programs. There remains a good deal of discussion in the amateur telescope making community over the use of glue and the addition of simple astatic devices in such cells.

Cells for large telescopes

Astronomical observatories require a much heavier and more complex mirror support cell. One notable example of the structure needed for such telescopes is the dual cell for the M1 mirrors of the 8.4 meter Large Binocular Telescope

Large Binocular Telescope

Large Binocular Telescope is an optical telescope for astronomy located on Mount Graham in the Pinaleno Mountains of southeastern Arizona, and is a part of the Mount Graham International Observatory...

 at Mount Graham International Observatory

Mount Graham International Observatory

Mount Graham International Observatory is a division of Steward Observatory the research arm for the Department of Astronomy at The University of Arizona. It is located in southeast Arizona's Pinaleno Mountains near Mount Graham....

. This is a multiple beam

Beam (structure)

A beam is a horizontal structural element that is capable of withstanding load primarily by resisting bending. The bending force induced into the material of the beam as a result of the external loads, own weight, span and external reactions to these loads is called a bending moment.- Overview...

 and truss

Truss

In architecture and structural engineering, a truss is a structure comprising one or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes. External forces and reactions to those forces are considered to act only at the nodes and result in...

 system which in turn supports a temperature maintenance and air flow system, six position actuators and the 160 pneumatic actuators which work its active optics

Active optics

Active optics is a technology used with reflecting telescopes developed in the 1980s, which actively shapes a telescope's mirrors to prevent deformation due to external influences such as wind, temperature, mechanical stress...

 system. This results in a huge assembly structure weighing about 28 tons without its mirrors. Such a mirror cell requires multiple mathematical steps of finite element analysis of its deformation under static and moving loading.

See also

• Amateur Telescope Making
  Amateur Telescope Making
  Amateur Telescope Making is a series of three books edited by Albert G. Ingalls between 1926 and 1953 while he was an associate editor at Scientific American. The books cover various aspects of telescope construction and observational technique, sometimes at quite an advanced level, but always in...
  
  - book series by Albert G. Ingalls
• Amateur telescope making
  Amateur telescope making
  Amateur telescope making is the activity of building telescopes as a hobby, as opposed to being a paid professional. Amateur telescope makers build their instruments for personal enjoyment of a technical challenge, as a way to obtain an inexpensive or personally customized telescope, or as a...
  
   - the practice of telescope making by non-professionals
• List of telescope parts and construction
• Optical telescope
  Optical telescope
  An optical telescope is a telescope which is used to gather and focus light mainly from the visible part of the electromagnetic spectrum for directly viewing a magnified image for making a photograph, or collecting data through electronic image sensors....
  
  
• PLate OPtimizer
  PLate OPtimizer
  PLate OPtimizer, or PLOP is a CAD program used by amateur telescope makers to design primary mirror support cells for reflecting telescopes. It was developed by telescope maker David Lewis, first described in 1999, and used to simplify calculations needed in the design of mirror support cells...
  
  
• Telescope mount
  Telescope mount
  A telescope mount is a mechanical structure which supports a telescope. Telescope mounts are designed to support the mass of the telescope and allow for accurate pointing of the instrument...
  
  
• Mirror mount
  Mirror mount
  A mirror mount is a device that holds a mirror. In optics research, these can be quite sophisticated devices, due to the need to be able to tip and tilt the mirror by controlled amounts, while still holding it in a precise position when it is not being adjusted.Precision mirror mounts can be quite...
  
  

External Resources

• Mechanical design of the 110 cm cruxis telescope